A young businessman, Philip, finds himself in a peculiar situation. He is changing his clothes in a locker room, which has an unfinished wall, when a blind woman walks into the next room. She begins undressing, oblivious to the fact that Philip is present. He takes to a high road, keeps his mouth shut and sneaks off.
This was all a set-up by a hidden camera show, Peeping Toms. The woman, Danielle, is, of course, not really blind– she is an actress in on the joke on the unsuspecting victim. For being a good sport (and not much of a pervert), the show gives Philip a consolation prize for dinner for two at a local nightspot. This prize gets him a date with Danielle, who received a gift of a new cutlery set for her time.
Over dinner and drinks, Philip and Danielle hit off. Things go well until Danielle’s creepy ex-husband crashes their date. They leave and go back to Danielle’s apartment, but Emil, the ex, follows them. Philip spots him through the windows down on the street. To give him the slip, Philip gets in his car and circles the block. Emil, content that Danielle is alone, leaves. Philip parks down the street and walks back to Danielle’s apartment. Free and clear from stalking eyes, the two new lonely hearts spend the night together.
The next morning, Philip wakes to the sounds of Danielle arguing in the back bedroom with her twin sister, Dominique, who has come to visit to celebrate their birthday. While dressing in the bathroom, Philip accidently knocks Danielle’s remaining medication down the sink drain. She calls the pharmacy and Philip goes to get the prescription. After the pharmacy, he stops at the bakery for a birthday cake for Danielle and her sister, who has sequestered herself in the back bedroom.
When Philip returns and presents the cake to who he thinks is Danielle, who’s asleep on the pull-out sofa bed, she stabs the hell out of him with a butcher knife. As he is bleeding out, Philip crawls to the window and manages to write “Help” in his own blood on the glass. Across the street, in another apartment building, is reporter Grace. She sees Philip and the blood message and quickly calls the police.
Danielle, in a lot of pain, has called Emil for help before the murder. He arrives in time before the police and helps Danielle clean the mess and hide the body. The police arrive, with Grace in tow, to find a normal apartment and Danielle who has a plausible explanation for everything. Grace is skeptical, she knows what she saw and she becomes determined to uncover the truth about her sparkling French Canadian neighbor (her Siamese twin is just the tip of the iceberg).
Sisters is a crazy little pseudo-slasher/mystery, although it’s not really much of a mystery. It’s more a madcap escapade into free-wheeling storytelling. The seed of a lot of director Brian De Palma’s future films can be found here in this one (it would pair well with Dressed to Kill, Body Double, or Raising Cain). Raising Cain may have the slogan “De Mented. De Ranged. De Ceptive. De Palma.”, but it started with Sisters.